JPH1054829A - Apparatus for measuring concentration of liquid phase ozone of ozone-process water and detecting apparatus for permanganate ion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly and continuously measure a concentration of dissolved ozone and permanganate ions in an ozone process water in a short time, by setting a UV cell for measuring an ultraviolet ray absorbance originated from the dissolved ozone in the sample water, etc. SOLUTION: A sample water is collected by opening, closing a water collection pump 1 and water collection adjustment valves 1a, 1b, and sent to a UV cell 8 from a mixer 7 via flow rate regulation valves 4a, 4b. An ultraviolet ray absorbance and a visible light absorbency are measured at the UV cell 8 on the basis of an ultraviolet ray absorbance measurement principle. Then, when the sample water is sent to the mixer 7, simultaneously, sodium thiosulfate in a medicine tank 5 is fed to the mixer 7 by an injection pump 6. The sample water is again sent to the UV cell 8 after ozone is dissolved and, subjected to the same measurement process. A concentration of dissolved ozone in the sample water is obtained by operations, and moreover permanganate ions are detected. The operation which is unlike a method for producing zero water by aeration is thus simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the concentration of liquid phase ozone and permanganate ion contained in ozonated water in advanced water purification treatment represented by ozone treatment.

[0002]

2. Description of the Related Art Generally, in order to purify raw water taken from a river or the like, a suspension is flocculated by pouring, mixing, stirring and retaining a flocculant in a flocculating sedimentation basin to precipitate and separate. This process incorporates algal killing and chlorination to remove chromatic components such as iron and manganese. However, in recent years, rivers are extremely polluted in the vicinity of large cities, and the content of chromaticity components including humic substances, which are precursors of ammonia and the carcinogenic substance THM (trihalomethane), is high. And ammonia react with each other to generate chloramine and consume more chlorine than necessary. As a result, there is a problem that the chlorine injection rate increases and THM increases.

[0003] From such a background, in recent years, a method of incorporating an advanced water purification treatment system into a water purification process for the purpose of removing the above-mentioned substances has been performed. This advanced water treatment method includes ozone treatment and biological activated carbon treatment.For example, ozone treatment is performed by an ozone treatment tower as an alternative to chlorination treatment, and chromaticity components and the like are further removed by an activated carbon treatment tower or a biological filtration tower. After filtration in a filtration pond etc., chlorination is performed and water is sent to a water purification pond. In particular, by performing the ozone treatment before the biological activated carbon treatment, it is possible to improve the tolerance to load fluctuation and the life of the activated carbon.

[0004] Since the above-mentioned ozone treatment aims at removing dissolved trace organic substances in water, it is necessary to control not only the amount of water but also the quality of water. Therefore, a liquid ozone concentration meter based on an ultraviolet absorption method or a diaphragm electrode method is used as a water quality measuring device for a process.

The liquid-phase ozone concentration meter based on the ultraviolet absorption method utilizes the principle that ozone absorbs ultraviolet light, and alternately uses sample water and target water (usually abbreviated as zero water) from which ozone has been removed. A method for determining the ozone concentration of sample water by introducing water into a measuring cell is known. In order to obtain the above-mentioned zero water, a means for dispersing the liquid phase ozone by applying aeration to the sample water containing ozone and removing the ozone is effective.

[0006] In addition to the above, a liquid phase ozone concentration meter based on a diaphragm polarographic method has also been put into practical use. In this method, a voltage is applied between a detection electrode and a comparison electrode sealed with a diaphragm together with an electrolytic solution, and the liquid passes through the diaphragm. Then, the liquid phase ozone concentration is determined from the current proportional to the amount of ozone diffused in the electrolyte.

On the other hand, when water contains permanganate ions, insoluble manganese dioxide (MnO ₂ ) is generated as follows by ozone treatment. Mn ²⁺ + O ₃ + H ₂ O → Mn ⁴⁺ + O ₂ + OH ⁻ Mn ²⁺ + 4OH ⁻ → Mn (OH) ₄ → MnO ₂ +
When H ₂ O, especially a manganese compound is oxidized with excess ozone, permanganate ion (MnO ⁴⁻ ) that is easily soluble in water is generated, and the water turns pink. Mn ²⁺ or Mn ⁴⁺ + 4O ₃ → MnO ^4- + 4O ₂ Permanganate ion reacts with dissolved organic matter to form manganese dioxide, so it may be retained for about 15 to 30 minutes after ozone treatment. In addition, by passing permanganate ions directly through the activated carbon layer, insoluble manganese dioxide reduced at the top of the layer is formed and accumulated as a layer of several cm. Processing technology ”).

[0008]

However, the liquid-phase ozone concentration meter of the ozonated water used in the above-mentioned advanced water purification system has the following various problems.
That is, as described above, using means for performing aeration in the sample water containing ozone to generate zero water,
Residual ozone and residual E2 are generated by stirring the sample water.
Since an organic substance which is a substance expressing 60 reacts, there is a problem that an ultraviolet absorbing substance other than ozone is removed and a measured value becomes inaccurate.

Furthermore, at low water temperatures, it takes a long time to carry out deozonization by aeration. In addition, iron or manganese in the sample water adheres to the aeration apparatus, thereby improving the deozonation properties over a long period of time. Another drawback is that it is difficult to maintain.

When water contains permanganate ions, the total manganese is reduced to 0.3 to 1.2 at the time of drought.
(Mg / l, dissolved state: 60-80%), and there are some difficulties in the treatment even by pre-chlorination. In particular, with an increase in the ozone injection ratio (the ozone injection rate per sedimentary dissolved manganese concentration), oxidation from divalent to trivalent proceeds, and the residual dissolved manganese ratio decreases rapidly. The reason why the dissolved manganese residual rate increases at an ozone injection ratio of 3 is considered to be due to the progress of oxidation to 7 valences due to excessive ozone injection (Murai et al., "Advanced Water Purification Experiment 2: Manganese Treatment"). , Excerpt from 47th Suidoken).

As described above, when manganese is excessively oxidized by the ozone treatment, permanganate ions are generated, and the treated water turns pink, which is also unsightly. This permanganate ion is insoluble in manganese dioxide. , And are trapped in the activated carbon layer. However, excessive injection of expensive ozone results in excessive oxidation, which is disadvantageous in cost.
The production of 7-valent manganese is regarded as a problem of excess ozone treatment, and particularly when lake water is used as a water source, manganese eluted from the lake bottom poses a serious problem in treatment.

In view of the above problems, the present invention provides a liquid phase ozone concentration measuring apparatus and a permanganate ion detecting apparatus which can accurately and continuously measure the dissolved ozone concentration in ozonated water in a short time. It is the purpose.

[0013]

According to the present invention, in order to achieve the above object, the water to be treated is ozone-treated.
An ozone treatment apparatus used in a process for removing dissolved trace organic substances in water, according to claim 1, a sampling system for ozone-treated sample water, and a sample water sampled from the sampled water is fed into the sample water from a light source. A UV cell for measuring the ultraviolet absorbance derived from dissolved ozone by receiving the passed light to a light receiver, a tank filled with a reducing agent for removing ozone in the sample water by a reduction reaction, And a liquid-phase ozone concentration measuring device having ozone-treated water, which comprises: an injection mechanism for quantitatively injecting the mixture into a mixing unit provided between the UV cells.

According to a second aspect of the present invention, an ozone-treated sample water sampling system, a first UV cell into which a deozone-treated sample water is fed by injecting a reducing agent, and the first UV cell
A second UV cell which is disposed in parallel with the cell and into which the sample water containing dissolved ozone is directly fed, a tank filled with a reducing agent for removing ozone in the sample water by a reduction reaction, and Provided is a configuration of a liquid-phase ozone concentration measuring device including an injection mechanism that quantitatively injects the mixture into a mixing unit provided between an aqueous system and a first UV cell.

According to a third aspect of the present invention, an ozone-treated sample water sampling system, a first UV cell into which a deozonized sample water is fed by injecting a reducing agent, and the first UV cell
A second UV cell which is disposed in parallel with the cell and into which the sample water containing dissolved ozone is directly fed, a tank filled with a reducing agent for removing ozone in the sample water by a reduction reaction, and An injection mechanism for quantitatively injecting the mixture into the mixing section provided between the aqueous system and the first UV cell, the ultraviolet absorbance derived from the turbidity and the like measured in the second UV cell and the permanganate The ultraviolet absorbance derived from permanganate ion was determined by taking the difference from the ultraviolet absorbance derived from the turbidity and the like measured in the first UV cell from the sum of the ultraviolet absorbance derived from the ion and the permanganate ion. Of the permanganate ion detecting device for detecting the generation of water.

According to a fourth aspect of the present invention, the ozone treatment tank is provided with an ozone generator, a generated ozone concentration meter, a dissolved ozone concentration meter, a discharged ozone concentration meter, and a controller and a controller for driving the ozone generator. The ozone gas obtained from the ozone generator is diffused into the raw water flowing into the treatment tank, and at the same time, the generated ozone concentration, the dissolved ozone concentration and the exhausted ozone concentration are measured, and the permanganate ion in the raw water is calculated based on the calculation. Permanganate ions in the ozonated water that detect the presence or absence and output a control signal to drive the ozone generator from the control unit to the controller to perform drive control to eliminate permanganate ions in the ozonated water A detection device is provided.

As the reducing agent, sodium thiosulfate or sodium tetrathionate is used.

Between the water sampling system and the UV cell, there is provided a built-in filter for removing suspended matter in the sample water to monitor the degree of contamination, and a filter for removing suspended substances in the sample water. A pipe washing water production unit for introducing washing water into the pipe and the cell at a large flow rate by switching the flow path is provided.

According to the liquid phase ozone concentration measuring device and the permanganate ion detecting device, when measuring the dissolved ozone concentration of the sample water, the sample water is sampled and then sent into the UV cell, and the sample cell water is then discharged into the UV cell. UV light absorbance (U) based on a known UV light absorbance measurement principle based on the light that has passed through the sample water.
V) and visible light absorbance (VIS) are measured. Next, in order to measure ozone-free water in the sample water in the same manner, the sample water sampled is sent to the mixing section, and at the same time, the reducing agent filled in the chemical solution tank is quantitatively measured using the chemical solution injection mechanism. Into the UV cell after decomposing ozone by the reaction of the reducing agent and ozone, and performing the same measurement operation to obtain the dissolved ozone concentration of the sample water by calculation,
And permanganate ions are detected.

According to the permanganate ion detecting device of the fourth aspect, ozone gas is diffused from the ozone generator to the raw water flowing into the ozone treatment tank via the air diffuser,
At this time, the generated ozone concentration, the dissolved ozone concentration, and the exhausted ozone concentration are measured and input to the control unit. The control unit detects the presence or absence of permanganate ions in the raw water, and at the same time, calculates the permanganate ion based on the calculation. Control is performed to reduce the amount of ozone injected into the ozone treatment tank so that ions are not detected. The control is performed by changing the manipulated variable of the ozone generator or by outputting a control signal for decreasing the concentration of ozone injected from the ozone generator.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, various specific examples of a liquid phase ozone concentration measuring apparatus and a permanganate ion detecting apparatus according to the present invention will be described with reference to the drawings. As described above, in the liquid phase ozone concentration measuring apparatus based on the ultraviolet absorption method, zero water must be generated. In this case, a substance having higher reactivity with ozone than an organic substance which is a residual E260 expressing substance is added. A method for removing ozone is considered.

Ozone can be removed by performing an oxidation-reduction reaction with a reducing agent using ozone as an oxidizing agent. Sodium thiosulfate is known as a reducing agent used in such a reduction method. According to the reduction method, ozone can be removed instantaneously, and the removal of residual E253.7-expressing substances by ozone can be prevented.

FIG. 5 shows 253.7 of dissolved ozone in the aqueous solution.
The ozone has an absorption band called a Hartley Band in the ultraviolet region, and has a maximum absorption at 253.7 nm for gaseous ozone and 260 nm for ozone in an aqueous solution. Liquid phase ozone densitometers based on the ultraviolet absorption method utilize this property of ozone. In this embodiment, 253.
The absorbance is measured using a low-pressure mercury lamp having a bright line at 7 nm.

FIG. 6 shows sodium thiosulfate in an aqueous solution.
It shows an absorbance of 53.7 nm, and it can be seen from FIG. 6 that sodium thiosulfate absorbs ultraviolet light having a wavelength of 253.7 nm.

The reaction between sodium thiosulfate and ozone is represented by the following equation. 2Na ₂ S ₂ O ₃ + O ₃ + H ₂ O → Na ₂ S ₄ O ₆ + 2NaOH + O ₂ (1) According to the literature (ozonization technology, p39, 1990),
The amount of ozonolysis per kg of sodium thiosulfate is about 0.41 kg. Further, when sufficient sodium thiosulfate is added to an aqueous solution containing residual ozone to reduce and remove residual ozone, the residual sodium thiosulfate is reduced to 253.7.
FIG. 7 shows the relationship between the absorbance in nm.

From this result, the product obtained by the reaction of the formula (1) does not absorb the ultraviolet ray of 253.7 nm, and the absorbance at 253.7 nm in the aqueous solution after deozonization shows the residual sodium thiosulfate and residual E253. It is understood that the substance is an organic substance which is a substance expressing .7.

FIG. 8 shows the relationship between the absorbance at 200 to 600 nm and the measurement wavelength of a potassium permanganate (KMnO ₄ ) solution used as a sample containing permanganate ions. According to FIG. 8, it can be seen that absorption peaks exist around the measurement wavelengths of 540 nm and 310 nm. Therefore, potassium permanganate was measured at a wavelength of 253.7 nm by the liquid phase ozone concentration measuring apparatus used in this embodiment.
It can be seen that it absorbs at any wavelength of 46 nm.

FIG. 9 shows measurement wavelengths of 253.7 nm and 546 n.
The relationship between the absorbance at m and the potassium permanganate (KMnO ₄ ) solution concentration is shown. The correlation coefficient between the absorbance and the concentration at both wavelengths is up to 0.5 (mg-Mn / l).
A very high linearity of 0.99 was obtained. In particular, when the absorption of 546 nm due to the pink color of the treated water due to the generation of permanganate ions is large, and there is no turbidity or other 546 nm absorbing substance in the sample water, 546 nm is used as the measurement wavelength, It was found that the amount of manganate ions could be estimated.

FIG. 10 shows the absorbance and the measurement wavelength of a mixture obtained by adding sodium thiosulfate to a 0.22 (mg-Mn / l) potassium permanganate solution so that the injection rate of sodium thiosulfate becomes 10.024 (mg / l). And the relationship between the absorbance of the mixed solution added so that the injection rate of sodium thiosulfate becomes 5.012 (mg / l) and the measurement wavelength.

FIG. 11 shows the result of 0.55 (mg-Mn /
1) The relationship between the absorbance and the measurement wavelength of a mixed solution added to a potassium permanganate solution so that the injection rate of sodium thiosulfate is 10.024 (mg / l) is shown.
In both figures, 0.22 (mg-Mn / l) and 0.55
(Mg-Mn / l) An example using only a potassium permanganate solution is also added.

FIG. 12 shows the relationship between the measured wavelength and the absorbance when only 5.01 (mg / l) sodium thiosulfate (Na ₂ S ₂ O ₃ ) was used, and 0.22 (mg-Mn / l) permanganese. The injection rate of sodium thiosulfate into the potassium acid solution is 5.
The relationship between the absorbance of the mixed solution added so as to be 01 (mg / l) and the measurement wavelength is shown.

10 and 11, when sodium thiosulfate was added to the potassium permanganate solution, the absorption peaks near 540 nm and 300 nm disappeared, and the pink color caused by permanganate ions disappeared by mixing.
Also, the absorbance at a wavelength smaller than 270 nm increases. It can be seen from FIG. 12 that this increase in absorbance is in good agreement with the absorbance of the added sodium thiosulfate.

From the above results, when sodium thiosulfate is excessively added to the sample water containing permanganate ion, the absorbance of the sample water almost coincides with the absorbance of the added sodium thiosulfate, and the sample water absorbs at a wavelength of 546 nm. It turned out to be no longer.

The first embodiment of the present invention described below utilizes an ultraviolet absorption type liquid phase ozone concentration measuring apparatus using this sodium thiosulfate as a chemical solution for deozonization, utilizing the characteristics of sodium thiosulfate described above. This is an example. The configuration of the first embodiment will be described with reference to the schematic diagram of FIG. 1. 1 is a water sampling pump, 1a and 1b are water sampling adjustment valves, 2 is a zero water production unit (F1), and 3 is a pipe washing water production unit. (PRE-F), 4
Reference numerals a, 4b, 4c, and 4d denote flow control valves, 5 a chemical tank, 6 a chemical injection pump, 7 a mixer, 8 a cell for measuring ultraviolet absorbance (hereinafter abbreviated as a UV cell), 9 a drain pipe,
0 is an overflow pipe.

The water sampling pump 1 and the water sampling adjusting valves 1a and 1b constituting the water sampling system are made of ozone-resistant material, and can continuously sample ozone-treated sample water. The chemical liquid tank 5 is filled with a sodium thiosulfate solution as a reducing agent. The chemical solution tank 5 is made of a material capable of storing sodium thiosulfate for a long period of time, and the chemical solution injection pump 6 has a function of intermittently injecting the chemical solution into the sample water using a highly quantitative pump.

The principle of measuring UV and visible light absorbance (VIS) by the UV cell 8 will be described with reference to FIG. Reference numeral 11 denotes a light source power supply unit, and reference numeral 12 denotes a light source lamp. The UV cell 8 is arranged near the light source lamp 12.
A light splitter 13 is disposed between the light source lamp 12 and the UV cell 8, and a light receiver 14 is provided on the optical path of the light splitter 13.
4 is connected to the reference signal line 15.

Behind the UV cell 8, the light source lamp 1
A photodetector 16 is arranged at a position facing 2, and a signal received by the photoreceiver 16 is input to a converter / calculator 18 via an amplifier 17. The converter / calculation unit 18 is provided with an E253.7 output unit 19 and an E546 output unit 20. Each of the output units 19 and 20 is connected to a display unit (not shown). The other end of the reference signal line 15 is connected to an amplifier 17.

In this embodiment, the detection unit of the UV cell 8 is 50 to
A continuous flow cell having an optical path length of 100 mm is used. The UV cell 8 has a cleaning mechanism using a wiper filled with a chemical solution such as hydrochloric acid because the UV cell 8 is easily contaminated by the adhesion of organic components in ozonized water, iron or manganese oxidized by ozone, and the like.

The light source lamp 12 is a low-pressure mercury lamp, and a low-pressure mercury lamp having a bright line at 253.7 nm is used as a light source. This lamp has a low intensity but has a bright line at 546 nm.

The operation of the first embodiment will be described below. First, when measuring the dissolved ozone concentration of the sample water, the water sampling pump and the water sampling adjusting valves 1a and 1b constituting the water sampling system are used.
The sample water is sampled based on the opening / closing operation of the sampler, and the flow rate adjusting valves 4a and 4b are opened to supply the sample water from the mixer 7 to the UV cell 8
Into the inlet 8a (FIG. 2). At this time, the flow control valves 4c and 4d are closed, and excess sample water flows out of the overflow pipe 10.

When the light source lamp 12 is turned on at the same time that the sample water flows into the UV cell 8, the light of 253.7 nm emitted from the light source lamp 12 is separated by the light separation splitter 13 before passing through the measurement cell. The signal is received by the optical receiver 14 and input to the amplifier 17 via the reference signal line 15. The light that has passed through the sample water in the UV cell 8 is
6, the signal is amplified by the amplifier 17, and then sent to the converter / calculation unit 18, where the UV absorbance (UV) and the visible light absorbance (VIS) are measured based on the known UV absorbance measurement principle. The data is output from the E253.7 output unit 19 and the E546 output unit 20 to a display unit (not shown).

Since the light separated by the light splitting splitter 13 and received by the light receiver 14 does not pass through the sample water, this light is input to the amplifier 17 via the reference signal line 15 to thereby make the light It is used as a reference value or a correction value of the measured value. The sample water for which measurement has been completed is U
The water is drained from the drain pipe 8 of the V cell 8.

By the above operation, signals of the absorbance at 253.7 nm of ultraviolet light (E253.7) and the absorbance of visible light at 546 nm (E546) having a high correlation with suspended matter or suspended matter are measured. In order to overcome the weak point "susceptible to turbidity", the detection unit uses E253.7 to E54
By subtracting 6, the addition of E253.7 due to turbidity is corrected. This allows measurement even if the sample contains a small amount of turbidity.

Next, the same measurement operation is performed on water from which ozone has been removed from the sample water. In this case, the sample water sampled in the water sampling system is sent to the mixing section 7 and simultaneously, the sodium thiosulfate filled in the chemical tank 5 is sent to the mixing section 7 using the chemical injection pump 6, Ozone is decomposed by the reaction of sodium thiosulfate and ozone based on the formula (1), and then sent to the UV cell 8, and the same measurement operation is performed. Based on the calculation formula described below, the dissolved ozone concentration and the concentration in the ozonized water are calculated. E other than dissolved ozone
Determine the absorbance of the 253.7 expressed material.

After the measurement, the inner wall of the UV cell 8 is liable to be contaminated by organic components in the ozonized water or iron, manganese, etc. oxidized by ozone, and is stored in a chemical tank (not shown) after one measurement. Using the 2-5% hydrochloric acid, the inner wall of the UV cell 8 is cleaned by the cooperation of a wiper rubber or the like (not shown).

The zero water producing section 2 is provided with E253.7 in the sample water.
The sample water can be treated using a filter that can remove substances and turbidity that expresses, and the treated water can be introduced into the cell via the flow control valve 4d. Since E253.7 of the treated water is zero, introduction of the treated water into the cell at a constant cycle has the advantage that the monitoring of the degree of contamination of the cell and the correction of the auto-zero can be performed automatically.

Further, the pipe washing water producing section 3 processes the sample water using a filter capable of removing suspended substances in the sample water, and after the above measurement is completed, switches the flow path by a flow control valve to transfer the treated water to a normal UV cell. 8 can be introduced into the pipes and cells at a flow rate greater than the flow rate. By the introduction of this washing water, the inside of the cell and the inside of the pipe are flush-cleaned,
The adhered dirt can be removed.

A method for obtaining the dissolved ozone concentration of the sample water using a cell having an optical path length of 100 mm will be described below. First, it is assumed that the sample water contains a dissolved ozone concentration t (mg / l) and a substance that expresses E253.7 other than dissolved ozone (this is referred to as a substance X). This sample water flow rate Q
(Ml / min) into the cell and 253.7 n of the sample water
m is measured (hereinafter simply referred to as absorbance). Assuming that the absorbance of the substance X is u (abs) and the absorbance of the sample water is α, the absorbance of dissolved ozone (abs) = a · the concentration of dissolved ozone (mg / l), where a, b, and c are constants. Absorbance (abs) = b · Sodium thiosulfate concentration (mg / l) Chemical amount required for deozonization in solution (mg) = c · Dissolved ozone (mg) in solution. Therefore, since the absorbance of the dissolved ozone contained in the sample water is at · t (abs), α = u + at · t.

Next, a chemical solution is injected into the sample water to remove ozone, and then the absorbance β (abs) is measured. The concentration of sodium thiosulfate (chemical solution) is s (mg / l), and the injection flow rate is q
(Ml / min). This injection flow rate q is made as small as possible. The chemical solution is injected into the sample water flowing at the flow rate Q (ml / min) by the chemical injector so that the flow rate can be q. At this time, the dissolved ozone concentration (mg / l) from which the chemical solution can be removed is:
(S · q) / {c · (q + Q)}. The concentration of the chemical solution consumed when the dissolved ozone is completely removed is ct
(Mg / l).

(1) When a chemical solution is sufficiently injected for deozonization, that is, when (s · q) / {c · (q + Q)}> t, the chemical solution consumed when the dissolved ozone is removed is c・ T · {Q (Q + q)} The remaining chemical is s · {q (Q + q)} − ct · {Q (Q + q)}, and the absorbance of the remaining chemical is b · s · {q (Q + q)} − ct · {Q (Q + q)}.

The absorbance β (abs) of the sample water is β = u + bs · {q (Q + q)} − ct · Q (Q
+ Q)｝. When β is subtracted from α, (α−β) = a · t−b · {q (Q + q)} − ct · t ·
{Q (Q + q)}.

The dissolved ozone concentration t (mg
/ L), t = {(Q + q) / a · (Q + q) + b · c · Q} · {α−β + (bs · q /) / (q + Q)} where Q｝ q , Q + q = 0, then t = {1 / (a + b + c)}｝ {α-β + (bsq / Q)} (2) a, b, c are constants, s, q, Q are known, α,
Since β is a measured value, from equation (2), the dissolved ozone concentration t
(Mg / l) can be calculated.

The following equation (3) is obtained from the measured value α. The absorbance of the substance X in the sample water is calculated using the equation (3).

By the above method, the dissolved ozone concentration and the absorbance of the substance X, ie, the E253.7-expressing substance other than the dissolved ozone in the ozonized water, can be measured.

This embodiment is suitable for intermittent measurement of dissolved ozone concentration over time or for measurement of dissolved ozone concentration in a gradual system. The detection unit of the present embodiment has one measuring cell, and measures the sample water intermittently. Since measurement is performed in the same cell, there is an advantage that an error due to a difference between cells does not occur.

Next, a second embodiment of the present invention will be described with reference to FIG. Since the basic configuration of the second embodiment is the same as that of the first embodiment shown in FIG. 1, the same components are denoted by the same reference numerals, and the description will not be repeated.

In the second embodiment, two measuring cells, a first UV cell 8a and a second UV cell 8b, are arranged in parallel in place of the UV cell 8 as a measuring cell for ultraviolet absorbance. It is. Then, the sample water deozone-treated by injecting sodium thiosulfate by the mixing unit 7 is supplied into the first UV cell 8a, and the sample water containing dissolved ozone is directly supplied to the other second UV cell 8b. Have been. The measuring operation itself is the same as in the first embodiment.

The operation of the second embodiment will be described below. That is, E253. Measured in the first UV cell 8a.
7 is the ultraviolet absorbance derived from organic matter in the deozonized water, whereas E253.7 measured by the second UV cell 8b is the ultraviolet absorbance derived from organic matter and the ultraviolet absorbance derived from dissolved ozone. Is the sum of

Then, by taking the difference between the measured values of the second UV cell 8b and the first UV cell 8a, the ultraviolet absorbance derived from dissolved ozone can be obtained. In particular, the converter / calculator 18 can calculate the dissolved ozone concentration by calculation using the UV signal and the UV-VIS signal. In particular, in the second embodiment, sample water whose dissolved ozone concentration changes frequently with time is sampled and continuously measured using the first and second UV cells 8a and 8b to reduce the dissolved ozone concentration for a short time. Suitable for the system required in.

When measuring the sample water containing permanganate ions based on the second embodiment, the first U
E546 measured by the V cell 8a is an ultraviolet absorbance derived from turbidity and the like in the deozonized water, whereas E546 measured by the second UV cell 8b is an ultraviolet absorbance derived from turbidity and the like. It is the sum of the absorbance and the ultraviolet absorbance derived from permanganate ions. Therefore, the second UV cell 8b
By taking the difference between the measured values of the first and second UV cells 8a, the ultraviolet absorbance derived from permanganate ions can be obtained. As described above, since the permanganate ion concentration has a high correlation with the absorbance at 546 nm, it is possible to detect the permanganate ion and estimate the concentration by calculating the difference between the measured values.

Next, a third embodiment of the present invention will be described. This embodiment is characterized by a method of performing ozone treatment control of raw water containing permanganate ions using an ultraviolet absorption dissolved ozone concentration meter. In FIG. 4, 21 is an ozone treatment tank,
22 is an ozone generator, 22a is an air diffuser disposed near the bottom wall in the ozone treatment tank 21, 23 is a generated ozone concentration meter,
24 is a dissolved ozone concentration meter, 25 is an exhausted ozone concentration meter, 26
Is a controller for driving the ozone generator 22;
7 is a control unit.

The measuring principle of the ultraviolet absorption type dissolved ozone concentration meter 24 is almost the same as the principle of measuring UV and VIS described with reference to FIG.

According to the third embodiment, potassium permanganate (KMnO ₄ ) is used as a permanganate-containing sample, flows into the ozone treatment tank 21, and the controller 26
The ozone generator 22 is activated based on the output of the above, and emits the ozone gas from the air diffuser 22a disposed near the bottom wall in the ozone treatment tank 21. At this time, the generated ozone concentration measured by the generated ozone concentration meter 23 and the dissolved ozone concentration meter 2
4 and the exhausted ozone concentration measured by the exhausted ozone concentration meter 25 are input to the control unit 27, and the controller for driving the ozone generator 22 based on the calculation in the control unit 27 A control signal is output to 26.

Injection of ozone gas is generally performed by one of constant control of ozone injection rate, constant control of dissolved ozone concentration, and constant control of exhausted ozone concentration.

From the relationship between the absorbance and the measurement wavelength and the relationship between the absorbance and the concentration of the potassium permanganate solution shown in FIGS. 8 to 11, the ultraviolet absorption type dissolved ozone concentration meter 2 was used.
4, the presence or absence of permanganate ions in the raw water can be detected.

When permanganate ions are detected by the normal ozone treatment, it is determined that ozone is excessively injected, and a signal is input to the control unit 27 so that the permanganate ions are not detected. Next, control for reducing the amount of ozone injected from the ozone generator 22 into the ozone treatment tank 21 is performed. The control amount is determined so as to eliminate permanganate ions in the ozonized water, or a control signal is output to the controller 26 so that the injected ozone concentration decreases. Excess ozone gas is guided to a waste ozone treatment device to be detoxified.

Next, a fourth embodiment of the present invention will be described. The third embodiment is characterized in that sodium tetrathionate is used in place of sodium thiosulfate which is a chemical solution for de-ozone filling in the chemical solution tank 5 of the first embodiment shown in FIG. ing.

FIG. 13 shows the absorbance of sodium tetrathionate in an aqueous solution at 253.7 nm. It can be seen from FIG. 13 that sodium tetrathionate absorbs ultraviolet light having a wavelength of 253.7 nm. Therefore, by employing sodium tetrathionate instead of sodium thiosulfate of the first embodiment and performing the same operation, the concentration of dissolved ozone in the sample water can be measured and permanganate ion can be detected.

[0069]

As described above in detail, according to the present invention, a sample water is sampled and then sent into a UV cell to measure the UV absorbance and the visible light absorbance based on the UV absorbance measurement principle. The reducing agent is quantitatively injected into the sample water sampled using the chemical liquid injection mechanism, and the ozone is decomposed by the reaction between the reducing agent and ozone, and then sent to the UV cell. Can be determined and permanganate ion can be detected.

Therefore, the conventional method of generating zero water by performing aeration is not required, so that the operation is simplified and the time required for deozonization even in a low water temperature period is shortened, thereby speeding up the measurement. Can be measured.

According to the third aspect of the present invention, the first UV cell into which the sample water deozonized by the injection of the reducing agent is sent, and the first UV cell is disposed in parallel with the first UV cell to dissolve the sample water. With the provision of the second UV cell into which the sample water containing ozone is directly sent, the difference between the ultraviolet absorbance derived from the turbidity and the like and the ultraviolet absorbance derived from permanganate ion measured by the second UV cell. The first U from the sum
By taking the difference from the ultraviolet absorbance derived from the turbidity and the like measured in the V cell, the ultraviolet absorbance derived from permanganate ion is obtained, and the generation of permanganate ion can be detected. In particular, the present invention is effective when applied to a system in which the dissolved ozone concentration frequently changes over time in a sample water, and the dissolved ozone concentration is determined in a short time.

In the present invention, the inaccuracy of the measurement value accompanying the removal of the ultraviolet absorbing substance other than ozone due to the reaction between the residual ozone and the organic substance which is the substance exhibiting residual E260 is eliminated, and the degree of contamination between the water sampling system and the UV cell is monitored. Dewatering due to the adhesion of iron and manganese in the sample water to the equipment during measurement by providing a zero water production part and a pipe cleaning water production part that introduces cleaning water into the piping and cells by switching the flow path Thus, the measurement accuracy can be maintained satisfactorily.

Therefore, according to the present invention, the dissolved ozone concentration and the permanganate ion in the ozonized water are measured and detected accurately and continuously in a short time, so that the water quality fluctuation of the ozonation raw water and the change of the ozone treatment condition are changed. It is possible to quickly respond to changes in water quality due to the ozone treatment conditions and control the operation of the ozone treatment tank to reduce permanganate ions with high accuracy. It is effective.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a liquid phase ozone concentration measuring apparatus according to the present invention.
The schematic diagram which shows an Example.

FIG. 2 is a schematic diagram showing the principle of measuring ultraviolet absorbance in the present embodiment.

FIG. 3 is a schematic diagram showing a second embodiment of the present invention.

FIG. 4 is a schematic diagram showing a third embodiment of the present invention.

FIG. 5 is a graph showing the absorbance at 253.7 nm of dissolved ozone in an aqueous solution.

FIG. 6: 253.7n of sodium thiosulfate in aqueous solution
The graph which shows the light absorbency of m.

FIG. 7 is a graph showing a relationship between residual sodium thiosulfate when sodium thiosulfate is added and absorbance at 253.7 nm.

FIG. 8 is a graph showing the relationship between the absorbance of a potassium permanganate solution and the measurement wavelength.

FIG. 9 is a graph showing the relationship between the absorbance at the measurement wavelengths of 253.7 nm and 546 nm and the concentration of the potassium permanganate solution.

FIG. 10 is a graph showing the relationship between the absorbance of a mixture obtained by adding sodium thiosulfate to a potassium permanganate solution and the measurement wavelength.

FIG. 11 is a graph showing the relationship between the absorbance of a mixture obtained by adding sodium thiosulfate to a potassium permanganate solution and the measurement wavelength.

FIG. 12 is a graph showing the relationship between the measurement wavelength and the absorbance when only sodium thiosulfate is used, and the relationship between the absorbance and the measurement wavelength of a mixed solution obtained by adding sodium thiosulfate to a potassium permanganate solution.

FIG. 13: 25 of sodium tetrathionate in aqueous solution
Graph showing the absorbance at 3.7 nm.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Sampling pump 2 ... Zero water production part 3 ... Pipe washing water production part 5 ... Chemical liquid tank 6 ... Chemical liquid injection pump 8.8a, 8b ... UV cell 11 ... Power supply part for light source 12 ... Light source lamp 13 ... Light separation splitter 14, 16 ... Receiver 15 ... Reference signal line 17 ... Amplifier 18 ... Converter / calculator 21 ... Ozone treatment tank 22 ... Ozone generator 22a ... Aeration tube 23 ... Ozone concentration meter 24 ... Dissolved ozone concentration meter 25 ... Exhaust Ozone concentration meter 26 ... Controller 27 ... Control unit

Claims (7)

[Claims] 1. An ozone treatment of water to be treated,
The ozone treatment equipment used in the process of removing trace trace organic substances dissolved in water, a water sampling system for ozone-treated sample water, and receiving light from the light source that has been sent and passed through the sample water from the light source A UV cell that receives ultraviolet light from the dissolved ozone and measures the ultraviolet absorbance derived from the dissolved ozone, a tank filled with a reducing agent that removes ozone in the sample water by a reduction reaction, and the reducing agent between the water sampling system and the UV cell. A liquid-phase ozone concentration measuring device, comprising: an injection mechanism for injecting quantitatively into a provided mixing unit. 2. By subjecting the water to be treated to ozone treatment,
An ozone treatment apparatus used in a process for removing dissolved trace organic substances in water, comprising: a water sampling system for ozone-treated sample water; and a first U into which a sample water deozonized by injection of a reducing agent is fed.
A V cell and a second UV arranged in parallel with the first UV cell and into which the sample water containing dissolved ozone is directly fed.
A cell, a tank filled with a reducing agent for removing ozone in the sample water by a reduction reaction, and an injection mechanism for quantitatively injecting the reducing agent into a mixing unit provided between the water sampling system and the first UV cell. A liquid phase ozone concentration measuring device characterized by comprising: 3. An ozone treatment of the water to be treated,
An ozone treatment apparatus used in a process for removing dissolved trace organic substances in water, comprising: a water sampling system for ozone-treated sample water; and a first U into which a sample water deozonized by injection of a reducing agent is fed.
A V cell and a second UV arranged in parallel with the first UV cell and into which the sample water containing dissolved ozone is directly fed.
A cell, a tank filled with a reducing agent for removing ozone in the sample water by a reduction reaction, and an injection mechanism for quantitatively injecting the reducing agent into a mixing unit provided between the water sampling system and the first UV cell. And the turbidity or the like measured in the first UV cell from the sum of the ultraviolet absorbance derived from the turbidity and the like measured in the second UV cell and the ultraviolet absorbance derived from the permanganate ion A permanganate ion detection device for obtaining permanganate ion by obtaining a difference between the ultraviolet absorbance derived from permanganate ion and the ultraviolet absorbance derived from permanganate ion to detect the generation of permanganate ion. 4. An ozone treatment tank is provided with an ozone generator, a generated ozone concentration meter, a dissolved ozone concentration meter, a discharged ozone concentration meter, and a controller and a controller for driving the ozone generator. The ozone gas obtained from the ozone generator is diffused into the incoming raw water, and at the same time, the generated ozone concentration, the dissolved ozone concentration and the exhausted ozone concentration are measured, and the presence or absence of permanganate ions in the raw water is detected based on the calculation. A permanganate ion detection device for outputting a control signal for driving an ozone generator from a control unit to a controller to perform drive control for eliminating permanganate ions in the ozonized water. . 5. The liquid phase ozone concentration measuring device and the permanganate ion detecting device according to claim 1, wherein the reducing agent is sodium thiosulfate. 6. The liquid phase ozone concentration measuring device and permanganate ion detecting device according to claim 1, wherein the reducing agent is sodium tetrathionate. 7. A zero water producing unit for monitoring a degree of contamination by incorporating a filter for removing turbidity in sample water between the water sampling system and the UV cell, and a filter for removing suspended matter in the sample water. The liquid-phase ozone concentration of the ozonized water according to any one of claims 1 to 3, further comprising a pipe cleaning water production unit which is incorporated and introduces a large flow of the cleaning water into the pipes and the cells by switching the flow path. Measurement device and permanganate ion detection device.